Crop response to foliar applied metal ion nutrients in the field is an extremely complex process. Efficacy depends on the nutrient status of the plant, the species in question and the timing of application and environmental factors. Many crops have a high need for metal ion nutrients such as zinc, iron, copper and magnesium but an accompanying inability to move these nutrients from the point at which foliar applied metal ion nutrients hit the leaf, to points through the crop where the metal ion nutrients are needed. For instance, almonds have a high zinc requirement but less than 3 percent of foliar applied zinc actually moves from point of interception to sites within the crop where the zinc can be effectively used.
As will be readily apparent to those of skill in the art, there are two challenges in attaining efficacy with foliar applied metal ion nutrients. These two challenges are: attaining penetration through epicuticular wax and movement of the nutrients from the leaf to other parts of the plant that require the nutrient.
Published US Patent Application 2012/0312059 teaches a liquid foliar nutrient which comprises 5-80% by weight of oil selected from mineral oils, vegetable oils, esters of fatty acids, aliphatic alcohols and mixtures thereof together with a surfactant and an essential element, selected from Fe, Mn, B, Cu, Mo, Co, Ni, Zn, Ca, Mg, Si, Se and mixtures thereof. In some embodiments, acidifiers and coupling agents are added. Examples provided for suitable acidifiers include lactic acid, propionic acid and citric acid. Examples of suitable coupling agents provided include alcohols, amines, alkylcarbonates, glycols and glycol ethers such as glycerine, dipropylene glycol, urea, ammonium acetate, aqueous ammonia and dipropylene glycol monomethyl ether. As discussed herein, it is believed that many of these optional additives may form complexes with the metals and prevent or hinder dispersion of the metals to the rest of the plant.
Chinese patent application CN101983954.09 describes an anti-virus composite nutrient solution which is prepared by mixing 2 separate solutions together. Solution A consists of Potassium sulfate 10 g, seven magnesium sulfate heptahydrate 30 grams, phosphoric anhydride 5 grams, boric acid 1 g, a water manganese sulfate 0.2 g, heptahydrate zinc sulphate 0.2 g, five water copper sulfate 0.2 g, ferrous sulphate heptahydrate 3 grams, molybdenum trisulfate 0.1 g, vitamin C 0.3 grams. Solution B consists of Calcium chloride 43 g, six water magnesium chloride 4.7 g and urea 2.3 grams.
Neither of these references deal with enhancing uptake of metal ion sulfates by a two part mechanism using a POD adjusting compound to prevent “lock up” by leaf wax and a urea transport enhancer to assist in moving metal ions through the plant to maximize nutrient enhancement from the available metal ions.